Wild Floivers 377 



coloured according to the places where certain groups 

 are most abundant, we find the same colours occurring 

 in smaller or larger patches, but those of the same 

 colour separated by great spaces of a different tint. 



The explanation of this problem seems to have been 

 solved by Edward Forbes. He, as well as many other 

 modern botanists, maintains that ' The climatic varia- 

 tions of the past are reflected in the fauna and flora of 

 the present,' and was probably the first to demonstrate 

 that the Glacial Age has left its distinct mark on tlie 

 flora of the present day. During the Glacial Age, the 

 Arctic species which are now found on mountains in 

 temperate climates, grew in the plains ; but as the 

 climate became milder, they receded to the far north 

 and the higli mountains, their places in the plains being 

 taken by new species. 



It has been already said how, not long since, geologi- 

 cally speaking, the whole of Norway and Sweden was 

 covered with an inland sea of ice, above which only 

 solitary mountain-tops arose, at which period the 

 majority of the present flora could not have existed in 

 Norway. But it is proved by the fact that specimens 

 of the present flora are found in coal strata older than 

 the Glacial Period, that the flora itself is older. For 

 instance, yew, fir, and spruce, hazel, willow, etc., have 

 been found in old peat-bogs of England and Switzer- 

 land, which are covered by the bottom moraine of the 

 inland ice. The present flora must have existed, there- 

 fore, in other countries which were free from ice during 

 the Glacial Age, and have immigrated to Norway as 

 the climate became milder and the ice receded. 



But to account for the variety of species existing in 



